1. Field of the Invention
The present invention relates generally curing UV-sensitive ink in a UV-ink printing process and, more particularly, to a reflector assembly for a UV-energy exposure system for such process.
2. Description of the Related Art
Ultraviolet-based inks and ceramic paints and pastes (compositions) are generally well known to skilled artisans. The compositions are used, for example, to form glass sheets, in general, and borders around the edges of glass sheets, in particular, which are used as windshields, sidelights, and backlights in motor vehicles.
Such a composition usually includes a mixture of metal oxides, which together act as a coloring agent for the composition. The metal oxides are non-reactive with one another and any elements or compounds with which they normally come into contact while being heated to about 1300xc2x0 F. The mixture of metal oxides can be controlled to get a selected color from the composition. Normally, in automotive applications, the selected color is black, and shades of gray are popular as well.
The composition also includes a glass frit that generally melts at a temperature below 1300xc2x0 F. The glass frit is the material that bonds the mixture of metal oxides to a glass sheet, for instance, and ensures that the mixture remains after the glass sheet has been cooled back to room temperature.
A UV-based organic medium is normally mixed with the metal oxides and the glass frit to allow the composition to be applied in a paint-application process. For example, if such a process is a screen-printing operation, then the UV-based organic medium carries, or transports, the metal oxides and the glass frit during the operation. The metal oxides, glass frit, and UV-based organic medium are mixed to form a liquid UV-based ceramic paint or paste that can be screen painted.
In the motor-vehicle application described above, the UV-based ceramic paint or paste is then applied to the glass sheet. After such application, the glass sheet is subject to UV radiation to set-up the UV-based ceramic paint or paste. The glass sheet is then heated to a temperature that softens the glass sheet sufficiently such that the glass sheet can be formed. The heating step also drives off any volatiles, such as burning off all organic material, remaining in the UV-based ceramic paint or paste after the UV-curing step. The heating step also firmly bonds the remaining portion of the UV-based ceramic paint or paste to the glass sheet.
The glass sheet and the UV-based ceramic paint or paste thereon are then engaged with, for instance, a fiberglass-covered forming die to form the heated glass sheet to a desired shape. After shaping, the forming die is removed from engagement with the glass sheet. After the forming die has been removed from engagement with the glass sheet and the UV-based ceramic paint or paste, the glass sheet may be cooled to obtain a formed glass sheet with ceramic paint or paste thereon. Normally, the glass sheet is rapidly cooled in a glass-tempering operation to achieve a tempered-glass product having the ceramic paint or paste thereon.
Many types of compositions of the above general type are well known to skilled artisans in this area. Further, the selection of the exact metal oxides, glass frit, and UV-based organic medium to use for such compositions is well within the skill of such artisans. Further, the manner in which the different materials may be mixed and varied to achieve the results desired in a particular application is also well within the skill of such artisans.
Recently, there has been significant improvement in the color formulations of the compositions. Meanwhile, multiple prints have become very popular in various industries, including the beverage and the perfume bottles industry. As such, these industries have been using the improved color formulations to make their respective wares. In the beverage industry, these wares may include glassware, for instance.
It may be desired to print glassware with, for example, three colors. In a conventional set-up, to cure the UV-sensitive compositions (after they have been applied to the glassware and before the glassware is heated to a temperature to heat fuse the paint ceramic color to the ware or so that the glassware can be formed), the glassware is typically passed through a series of UV ovens, the number of ovens depending upon the number of print requirements. In this way, the glassware is subjected to UV radiation to set-up the compositions such that they are bonded to the glassware.
A separate screen-printing station is typically used ahead each of the UV ovens. The glassware, with the UV-sensitive compositions printed thereon, is routed through an enclosure, such as a set of doors, of each of the UV ovens to allow the glassware to pass through the UV ovens, as escapement of UV energy from the UV ovens is restricted. While the glassware is in the ovens, it is exposed to a UV source within an enclosed chamber defined by each of the UV ovens.
As can easily be seen, this UV-energy exposing system for curing UV-sensitive inks in a UV-ink printing process takes the glassware to the UV source. The system of the related art can use much space, require much handling of the glassware, and require much time between consecutive printing operations in multiple-print requirements. In addition, with the system of the related art, a new set of equipment, having high initial investment cost, will be required to make use of the new UV-based inks and ceramic paints and pastes.
This system also applies to UV sensitive compositions that do not have any ceramic or glass inclusions. Decorations consisting of just organic colors and UV sensitive binders are used in the container, perfume, and beverage industry. In these cases, the decoration process is complete once the ware is exposed to the UV light. The bond to the substrate and other durability attained are enough for most uses.
Thus, there is a need in the art for a UV-energy routing system for a UV-ink printing process that brings the UV energy to the glassware, does not use much space, does not require much handling of the glassware, and does not require much time between consecutive printing operations in multiple-print requirements, and makes use of the new UV-based inks and ceramic paints and pastes.
Additionally, there is a need in the art to provide a reflector for a UV-energy routing system. There is also a need in the art to provide a reflector that directs energy by reflection on two stations simultaneously. Therefore, there is a need in the art to provide a reflector assembly that meets these desires.
Accordingly, the present invention is a reflector assembly for a UV-energy exposure system for a UV-ink printing process. The reflector assembly includes a funnel adapted to be connected to a UV energy source to funnel UV energy from the UV energy source longitudinally and a reflector connected to the funnel to redirect the UV energy from the funnel laterally to an object location.
One advantage of the present invention is that a reflector assembly is provided for a UV-energy exposure system for a UV-ink printing process that brings the UV energy to the substrate. Another advantage of the present invention is that a reflector assembly is provided for the UV-energy exposure system that does not use much space. Yet another advantage of the present invention is that the reflector assembly is placed in between two printing stations and directs the energy by reflection onto the two stations simultaneously. Still another advantage of the present invention is that the reflector assembly can be used to direct the energy to only one station if required.